If that 35 is a minimum temperature with temperatures in the 40's and 50's more the rule, I would say go for it. It may be a bit on the cold side but dry indoor winters in the north can be hard on citrus. If, however, the average winter temps are closer to that 35, that is too cold. Is there a way to get that sun room somewhat milder? I move my citrus into an attached garage for the winter. The minimum temp is between 35-40 (max average 50s). I have successfully overwintered meyers and eureka lemons, calamondin, kumquats, valencia, navel, and blood orange, limequats, and citron under these conditions. They are all now out on the patio and flowering profusely.

Njoasis there's no way to increase the heat in the sunroom.
So are you saying that 35 degrees would be to cold for it? I haven't actually taken the temp out there. I am guessing about the 35 range. I now that it doesn't get any colder than that out there. It may get closer to 40 (max)but I know for sure not lower than 35.
Do you think I should give it a try?
Thhanks.
Grice

You should not have discarded your Meyer Lemon, nor should you have cut the leaves from you Calamondin. Spider mites are a very easy insect to control, using a 1 percent horticultural oil spray. You can purchase horticultural oils at any Home Depot, or most all nurseries. Two popular trade names are Volk and Ultra Fine Oils. Spray in the morning or late in the evening. Further horticultural oils are extremely safe to use as they are completely non toxic. If you have space for your tree inside the 70F room you should put the tree there, and achieve growth throughout the winter months. If the temperature in the sunroom never dips below 35 the tree would probably make it through the winter, but there would be no growth.

I am confused about what the conditions in your room are like. If you are saying that the sun room temp is close to 35 degrees throughout the winter, then I would say yes it is way too cold. What are the average daytime max temps like in your sunroom in the winter?? The minimum temperature is not the only number to worry about.

Grice, if it doesn't drop below 35, it should be okay, but I'd keep the tree outside as long as possible to adapt. When temps drop below, say 38F then place in the sun room. This will prevent plant from sitting in cold winds which also reduces temps (wind chill)
Do you have electrical outlets in this room? You can always place Christmas lights around soil..
You'll also have to be extra careful when it comes to watering..soil don't dry out as fast..and you don't want soil to stay wet.
In the meantime, I'd foliar spray w/Fish Emulsion which works as of course a fertilizer, and an insecticide. Toni

Silica everyone tells me that spider mites are so easy to deal with. That has not proven to be the case in my situation. Safer Soap and homade concoctions had no effect. I was at my wits end when I cut the leaves off of the calamondin. The leaves were mollted and some were yellowing. Would those leaves have reverted back to a natural green? Are the products that you mention the same as a neem oil? I want to try Safer's BioNeem in my efforts to combat the mites.
Njoasis, the max temperature is between 35-40.
No Toni I have no outlets out there. I think I may just use the trial and error method. I'll try the tree out there and see what happens.
Toni,what do you know about BioNeem? Is it a good product to use ? I wanted to email you and ask abo0ut the calammondin but didn't want to be a pest.
Thanks everyone.
Grice

In my opinion, 35-40 as a MAXIMUM winter temperature is too cold to overwinter a calamondin. I was hoping that your maximum averages were more like the 45-55 degree range that I have found successful for overwintering of many citrus. Maybe someone out there will be able to report cold success at a lower temperature. If my averages were borderline freezing, I wouldn't chance it and would suggest overwintering someplace milder.

grice, No UltraFine and Volk Horticultural oils are not the same as Neem Oil. Horticultural oils are the standard in the Citrus industry for the control of most all insects. Professionally (commercial growers) no one uses Safer Soap. Safer Soap is fair to OK on aphids, but does not do a very good job on spider mites. As far as winter temperatures, temperatures below 28F can kill a citrus tree. Temperatures below 32F are considered dangerous. Temperatures below 55F the tree will live, but there will not be any growth at all. Temperatures at or above 65F during the winter will provide tree growth.